nosql database schema design

Tags: schema change high concurrency balanced data migration split infinite load balancing delayThe design of database extensibility Architecture Http://mp.weixin.qq.com/s/gI6j_TyjJ4jEb-i8HstFawProblems and solutions to be considered in the sub-list of http://www.jianshu.com/p/32b3e91aa22cInfinite Capacity Database arc

primary key to either party can 1:n : For example UserInfo and cardinfo are on the registration side is 1:n the Relationship UserInfo(userid,password,username,userlevel) Cardinfo(cardno,balance,cardstate) After conversion Cardinfo(cardno,userid,balance,cardstate) The primary key is placed on the n - side N:m : For example UserInfo and cardinfo are in the recharge aspect is n:m Relationship ( One user can recharge multiple cards, one card can be recharged by multiple users ) Cardinfo(cardno,b

.* * Set F for a set of function dependencies on the attribute set U, x, y belongs to U,x->y can be derived from F according to Armstrong Axiom sufficient and necessary condition is Y belongs to x+ (f).* * If g+=f+, it is said that the function dependency set F overrides G or f is equivalent to G.The sufficient and necessary condition of **f+=g+ is that f+ belongs to g+ or G belongs to f+;* * If the function dependency set F satisfies the following conditions, it is said that f is a minimum func

, it is necessary to make further judgments.Since b→a,a→e,ac→b are all kept (because their elements are in R1), we have to judge whether D→a is also maintained.For d→a application algorithm two:Result=dFor R1,result∩r1=ф (empty set, can not find the empty set of symbols, use this expression), T=ф,result=dAgain to r2,result∩r2=d,d+ =ade, T=d+∩r2=d,result=dThe result does not change after a loop, so the last Result=d does not contain a, so d→a is not persisted and the decomposition is not dependen

According to the second paradigm, the primary key is required. The primary key is still unique, and the primary key is also referenced as a foreign key to establish a relationship between the table and the table. Discuss the primary key from these aspects (the database is Oracle):1. Naming the primary keyRecently seen because of the reason that the schema uses hibernate, causing all primary key names to be